The hail storms in melbourne and whyalla have once again highlighted the problems of box gutters particularly where they are undersized or do not have an overflow mechanism.
Box gutter overflow detail.
The scupper is locked and soldered to the closure flange on all sides.
The outside detail is similar to detail 10 5d except that conductor heads and downspouts are not required.
Square or round ppc aluminium downpipes.
In my last article i discussed the emergence of the issue of provision for overflow in external eaves gutters or more specifically the lack of provision for overflow.
Any box gutter relying on a pipe or a slot for overflow can get blocked.
Peter coll provides a timely update regarding the provision for overflow and box gutter compliance.
Gutter replaced overflow inserted to reduce likelihood of damage but look at the quality of the workmanship with the overuse of silicone.
This free online box gutter calculator will calculate the size of box gutters and sumps with a side overflow in accordance with the australian plumbing code as nzs 3500 3 2003 part 3 storm water drainage.
If the box gutter has no overflow provisions this causes a waterfall over the sides of the box gutter typically running down the walls.
You can find these precut gutter splash guards about 3 in brown and white aluminum at a home center but you could easily make your own out of aluminum or sheet metal and spray paint them to match your gutters.
The most fail safe are the ones with no ends.
Internal and external corners stop ends t sections sumps overflows and weirs.
Holes through the splash guard and the gutter.
Drill rivet holes for the gutter splash guard.
Outlets box gutter outlets must discharge through either a rainhead or sump.
Overflow box gutters must have independent overflow provision discharging to the atmosphere.
So in this situation consider a larger than required opening especially if the roof is likely to catch leaves or balls.
On the roof side overflow scuppers can be detailed similar to detail 10 5d.
This has become a big issue in the past few months particularly in victoria and is going to be a new section in the upcoming.
The detail shows an alternate method of constructing either type of scupper.
As an alternative the top of the rainhead may be installed so that it is no higher than 50 per cent of the flow depth of the box gutter consistent with saa hb39 installation code for metal roof and wall cladding section 5 clause 5 7 3 and figure 5 7 3 to prevent internal flooding or damage to the building or contents see figure 2.
Downpipes available in lengths up to 6m.
The total flow is used to size the sump and overflow.
Support the entire weight of the gutter and sumps when full of water as well as a trafficable load at any point in the gutter and sumps.
Box gutters box gutters under the code come with complete overflow designs.
The side with the maximum flow is used to size the box gutter.
Layout box gutters must.
Square section pre coated steel downpipes.
